A device of this type is known from, for example, U.S. Pat. No. 5,737,902. The device described therein comprises a supply container for pharmaceutical products and a feed device with at least one feed channel for conducting the pharmaceutical products by means of gravity from the supply container into the packaging receptacles. The supply container is usually moved up and down to ensure that the pharmaceutical products are dispensed individually into the guide channel, in which the pharmaceutical products rest on top of each other and from which they are then dispensed downward sequentially into a drop chute. The drop chute in turn changes the direction of the tablets, which are at first oriented vertically, toward a horizontal position and conducts the tablets into the packaging receptacles, such as the pockets of a blister pack.
Instead of the sequential lowering of the tablets by means of laterally displaceable stacking trays as described in U.S. Pat. No. 5,737,902, the upper area of the guide channel can also comprise elaborate structures for singling out and conveying the tablets. Certain geometries of the guide channel are proposed for this purpose. These include a spiral geometry (see EP 1 391 386 A2) and a zigzag geometry with a three-dimensional component (see EP 1 698 554 A1).
In all these devices, plastic parts are preferably used to keep the cost down and to minimize the weight of the device. In some areas, it is possible for undesirable electrostatic charges to build up, which can interfere with the function of the packaging device.
For example, as a result of the up-and-down movement of the supply container, electrostatic charges are generated on the rubbing surfaces of the supply container and the feed tube, as a result of which an electrostatic field of considerable strength can develop, which can block the flow of the pharmaceutical products through the feed tube.
It is also possible for electrostatic charges to be generated by the sliding friction which occurs in the lower area of each drop chute at the point where the tablets change direction along their sliding path. These built-up electric charges can prevent the products from being deposited in the pockets.